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Cardiovascular-risk reduction: initial diuretic therapy compared with calcium-antagonist (felodipine) therapy for
K Sudhir1, G L Jennings, A Bruce
1Clinical Research Unit, Alfred Hospital and Baker Medical Research Institute, Prahran, Vic.
Insights
Felodipine, a calcium-antagonist, proved more effective than diuretic therapy for hypertension. It offered better blood pressure control, fewer metabolic side effects, and a greater reduction in cardiovascular risk.
Area of Science:
- Cardiology
- Pharmacology
- Internal Medicine
Background:
- Hypertension drug therapy has not significantly reduced coronary mortality.
- First-line antihypertensive treatments require evaluation for overall cardiovascular risk reduction.
Purpose of the Study:
- To compare felodipine (calcium-antagonist) with diuretic therapy as a first-line treatment for hypertension.
- To assess the effects of these regimens on overall cardiovascular risk over six months.
Main Methods:
- A randomized study comparing felodipine and diuretic therapy.
- Blood pressure, serum potassium, plasma renin activity, serum cholesterol, serum triglyceride, and plasma noradrenaline levels were monitored.
- Cardiovascular risk percentile score was calculated using Multiple Risk Factor Intervention Trial data.
Main Results:
- Both regimens lowered blood pressure; felodipine achieved control in 90% of patients as monotherapy, while diuretics required additional agents in 50%.
- Diuretics caused significant decreases in serum potassium and increases in plasma renin, cholesterol, and triglycerides.
- Felodipine did not affect these metabolic markers but increased plasma noradrenaline; it resulted in a greater reduction in cardiovascular risk percentile score (45% vs. 29%).
Conclusions:
- Felodipine is an effective monotherapy for hypertension with fewer metabolic side effects compared to diuretics.
- Felodipine demonstrates a superior reduction in cardiovascular risk when compared to diuretic therapy at equivalent blood pressure control.
- These findings suggest felodipine as a favorable first-line antihypertensive treatment option.
Abstract:
Drug therapy for hypertension has failed to demonstrate a significant reduction in coronary mortality. We compared a calcium-antagonist agent, felodipine, with diuretic therapy as a first-line antihypertensive treatment in a randomized study, to assess the effects of six months of each regimen on over-all cardiovascular risk. Both regimens lowered blood pressure to less than 85 mmHg by one month. Felodipine alone was sufficient to control blood pressure in 90% of patients, while 50% of patients who were receiving diuretic therapy required a second agent for control. Diuretic therapy produced a 10% fall in serum potassium levels (P less than 0.001) and a three-fold increase in plasma renin activity (P less than 0.005) by one month; and a 6% rise in serum cholesterol levels (P less than 0.05) and a 38% rise in serum triglyceride levels (P less than 0.05) by three months. Felodipine did not influence these measurements, but caused a 43% increase in plasma noradrenaline levels by one month of therapy (P less than 0.025). In both groups, a significant fall occurred in the risk percentile score at six months, as calculated from the Multiple Risk Factor Intervention Trial data. However, the decrease was significantly greater in the felodipine group at six months (45% compared with 29%; P less than 0.05). Thus, when doses were titrated to achieve equivalent effects on blood pressure, felodipine had the advantages over diuretic treatment of being effective as monotherapy, of having fewer metabolic effects, and of reducing cardiovascular risk to a greater degree.